diff --git a/Appraisals b/Appraisals
index 4eafbd31c..d637b6586 100644
--- a/Appraisals
+++ b/Appraisals
@@ -1,4 +1,6 @@
 appraise "rails60" do
+  gem "drb"
+  gem "mutex_m"
   gem "rails", "~> 6.0.3.4"
   gem "sprockets-rails", "~> 3.4"
 end
diff --git a/gemfiles/rails60.gemfile b/gemfiles/rails60.gemfile
index 05bdfd45b..a2c1162cc 100644
--- a/gemfiles/rails60.gemfile
+++ b/gemfiles/rails60.gemfile
@@ -19,6 +19,8 @@ gem "unicorn"
 gem "cssbundling-rails", "~> 1.4"
 gem "jsbundling-rails", "~> 1.3"
 gem "sprockets-rails", "~> 3.4"
+gem "drb"
+gem "mutex_m"
 gem "rails", "~> 6.0.3.4"
 
 group :development, :test do